The demand for multimedia applications in mobile communications has been growing at an astounding rate. Today, a user can send and receive still images, as well as download images and video from the Internet, for viewing on a mobile unit or handset. The integration of the digital camera into the mobile unit has further contributed to the growing trend in mobile communications for multimedia functionality.
Given the limited amount of resources like battery capacity, processing power, and transmission speed associated with a mobile unit, effective digital imaging processing techniques are needed to support multimedia functions. This requires the development of more sophisticated hardware and software that reduces computational complexity for multimedia applications while maintaining the image quality. The development of such hardware and software leads to lower power consumption and longer standby time for the mobile unit.
One facet of the digital imaging process involves removing blurriness from a picture. Blurriness may be caused by hand jitter. Hand jitter is caused by the movement of the user's hand when taking a digital picture with a camera. Even if the user is unaware of the movement, the hand may be continually moving. The movements are relatively small, but if the movements are large relative to the exposure time, the digital picture may be blurry. An object or person in the picture may appear to be moving. Blurriness may also be caused by an object/person moving when a picture is being taken. Blurriness may also be caused by limitations of the optical system used to capture the pictures.
Under low lighting conditions, a digital camera, for example, one found in a mobile unit, takes a longer time to register a picture. The longer exposure time increases the probability that the slight movements produced by the hand may lead to blurriness. Similarly, the longer exposure time increases the chance that the movement by the object/person may be large relative to the exposure time.
Current techniques for compensating for camera movements involve the use of small gyroscopes or other mechanical devices. None of the techniques seem to have an acceptable way to digitally compensate for the camera movements, especially under low lighting conditions. It would be desirable to reduce the amount of blurriness in a digital picture with efficient processing resources suitable for mobile applications under all conditions.